Harvesting Ultrasonic Sensors

With many modern cars coming equipped with an array of ultrasonic sensors mounted in the bumpers, it stands to reason that many junk yards have them too. [jimk3038] points out that, unless they’re crushed, they’re probably good. The list of features on these is pretty long, including being short proof, water proof, EMF proof and fast. These tough little suckers can be used in a multitude of projects and can have a range of roughly 2 meters. [jimk3038] documents in great detail how to use these things as well as offering some sample code to get you started. Why didn’t we think of this?

once again an idea I had that far outstretched my budget or electronic comprehension. I’ve been wanting to use some of these as a proximity alarm system on my car. would be an awesome alternative for many of the current expensive systems on the market today. I would imagine having a carpc connected with the cell towers could also alert you via sms to proximity. with an added camera and a bit of code you could even get a picture of the crime and call the police. ahhh the imagination of a student hard at work on things other than homework. lol

@Renee Yup. Bring your own tools, wander around and take what you like. Pay on your way out. (At least thats how they work where I am.)

Ultrasonic sensors aren’t the only cheap takeouts from cars. I have a road following windshield mounted camera that’s just begging for a project. A high quality camera mounted to an ARM micro, heavily ruggedized. For basically nothing.

This is great, I used to work in a body shop, and would pick what I could. Broken tail light got me 60+ high wattage LEDs, part of a prius, loads of large capacity capacitors, more relays and fuses than I know what to do with, motors, and random boards to recycle components. I have 1 of these, used to be 2, but I didn’t know what I was doing and let the smoke out of one. Thanks for the article, been waiting for something like this.

It seems like different states have different rules about junk yards. I know I could never find a decent junkyard that was open to the public in New Jersey, but if you cross the bridge into PA there are like 3 of them within a 5 mile radius.

Prices are usually ridiculously low, but of course it’s a real gamble as to what you will find in there. The junk yards I have been to certainly never had anything new enough for ultrasonic parking detectors, all the cars were early 1990’s and older.

How do these work? 12v to them and they close a contact when an object gets to about 6 ft away? Some can detect relative distance but probably need an arduino or the like to interpret the analog signal?

As people have touched on, there are two kinds of junk yards:
The kind where you go out with tools, disassemble the car yourself, take the parts you want, and pay some small amount for what you’ve got,
and – The kind where they pull the parts, and charge you much closer to the retail value of the part.

Obviously you’d want to go to the former. I know Pick-n-Pull is one such place. They’re all over California, but there are some dotted around the rest of the country.
-Taylor

Tom 90% of UK Scrap yards are the pick-n-pull type. Just wander in, the scruffier the better – don’t take a bag, just a screwdriver or two, a pair of pliers and a socket set and say you just want a mooch. They should be quite accomodating. I can’t speak for the rest of the country but Brum has dozens of decent scrappers.

i found that for many non-car projects the junkyard prices aren’t that great.
the reason is that car parts are overpriced and junkyards sell at a certain percentage compared to new.
that makes general non-automotive parts (relatively) pricey: a broken cordless drill might be a better source for a 12v motor than one pulled from a vent control, because at the junkyard it is still a replacement part not just a motor.

same goes for water pumps, switches, and probably ulrasound transceivers. unless you got a nice junky junk yard that doesn’t act as a used car parts business, thrift stores or surplus stores will be cheaper.

@Daniel It was apparently a 2008 Cadillac, don’t remember the model. It was stuck to the windshield(inside) above and behind the rear view mirror. It watches the lines on the road and alerts the driver when it thinks they’re straying out of the lane.